It looks like live streaming could be coming to a future generation of the iPhone and/or iPod devices. We've just come across this IETF submission containing Apple's spec for HTTP Live Streaming which describes a protocol for transmitting unbounded streams of multimedia over HTTP. According to the document, the protocol supports encryption of the media and the provision of alternate versions of the stream. The media data can also be transmitted after it's created, allowing it to be received in near real-time.

Could this mean live streaming is coming to our iPhones?

From our understanding of the documentation, this live streaming functionality will work using Playlist files located on the internet with a unique URI (uniform resource locator.) The Playlist itself will consist of a list of URIs each of which will point to a media file which is a segment of a single media stream.

The Playlists will be Extended M3U Playlist files, a standard playlist file format originally implemented by the Winamp player. These M3U files are plain text documents that contain the location of the media files that should be played. Originally, M3U files only supported audio playlists, but over the years they came to support video as well.

In the new specification, the M3U Playlist will extend the standard file format by defining additional tags called EXTM3U and EXTINF. The first of those two simply designates this playlist file as an extended M3U file and the second, EXTINF, is the record marker that describes the media file identified by the URI that follows it in the following format:

   #EXTINF:<duration>,<title>

The document then goes on to describe how this new specification should operate in more detail - you can read it in its entirety here.

The big question is, what does this really mean? Is a future version of iTunes going to support streaming music and video from our PCs to our iPhones and iPods, or will we be streaming directly from an Apple server instead? Either way, having that option could free up our disk space considerably on our devices - perhaps so there's more room for apps?

Perhaps it's in preparation for the upcoming camcorder functionality rumored to be coming in the next gen iPhone. Once people start saving video files to their hard drives, those disks could fill up fast. Why not make some room by letting us stream our media instead?

Then again, maybe Apple just felt it was time to take advantage of cloud computing and stop limiting how much we carry with us based on iPhone/iPod disk size and the size of our PC hard drives. If so, that would be a fantastic feature. This author knows from personal experience that, in our household, we recently purchased all five seasons of a particular hour-long TV show and lost 30 some GBs on our PC's hard drive in the process. Being able to stream instead of download, in this case, would have been a huge benefit.

A final theory is that Apple is simply getting the jump on Microsoft, who proposed a similar adaptive video stream a year ago called Smooth Streaming but didn't submit it to IETF to make it an RFC.

We don't know how live streaming is going to be put into use right now - we can only theorize. All we know is that it's been developed so we're hoping we'll find out sooner or later. Take a gander at the spec yourself and share your theories with us in the comments section below.